quick commit

shaders/A2Task1KernelDecompositionUnroll.comp

@@ -9,16 +9,106 @@ in uint  gl_LocalInvocationIndex;
 */
 layout(local_size_x_id = 0, local_size_y = 1, local_size_z = 1) in;
 
-layout(push_constant) uniform PushStruct {
-    uint size;
+layout(push_constant) uniform PushStruct
+{
     uint offset;
-} p;
+}
+p;
 
-layout(binding = 0) buffer inBuffer { uint v[]; };
-layout(binding = 1) buffer outBuffer { uint g_v[]; };
+layout(binding = 0) buffer inBuffer
+{
+    uint v[];
+};
+layout(binding = 1) buffer outBuffer
+{
+    uint g_v[];
+};
 
 // TODO: Shared variables
+// 512 Elements but initial reduction is done
+const uint bufferSize = 256;
+shared uint[bufferSize] localBuffer;
 
-void main() {
-    // TODO: Kernel implementation
-}
+void main()
+{
+    uint tid    = gl_LocalInvocationID.x;
+    uint gid    = gl_WorkGroupID.x;
+    uint offset = gid * bufferSize;
+
+    uint idx1 = offset + tid;
+    uint idx2 = offset + tid + gl_WorkGroupSize.x;
+
+    uint val1 = 0;
+    uint val2 = 0;
+
+    if (idx1 < p.offset)
+        val1 = v[idx1];
+    if (idx2 < p.offset)
+        val2 = v[idx2];
+
+    localBuffer[tid] = val1 + val2;
+    barrier();
+
+    // Reduction in shared memory (unrolled for last 5 steps)
+    for (uint s = gl_WorkGroupSize.x / 2; s > 32; s >>= 1)
+    {
+        if (tid < s)
+            localBuffer[tid] += localBuffer[tid + s];
+        barrier();
+    }
+
+    // Unrolled tail with full barriers for safety on Vulkan
+    if (gl_WorkGroupSize.x >= 64)
+    {
+        if (tid < 32)
+        {
+            localBuffer[tid] += localBuffer[tid + 32];
+            barrier();
+        }
+    }
+    if (gl_WorkGroupSize.x >= 32)
+    {
+        if (tid < 16)
+        {
+            localBuffer[tid] += localBuffer[tid + 16];
+            barrier();
+        }
+    }
+    if (gl_WorkGroupSize.x >= 16)
+    {
+        if (tid < 8)
+        {
+            localBuffer[tid] += localBuffer[tid + 8];
+            barrier();
+        }
+    }
+    if (gl_WorkGroupSize.x >= 8)
+    {
+        if (tid < 4)
+        {
+            localBuffer[tid] += localBuffer[tid + 4];
+            barrier();
+        }
+    }
+    if (gl_WorkGroupSize.x >= 4)
+    {
+        if (tid < 2)
+        {
+            localBuffer[tid] += localBuffer[tid + 2];
+            barrier();
+        }
+    }
+    if (gl_WorkGroupSize.x >= 2)
+    {
+        if (tid < 1)
+        {
+            localBuffer[tid] += localBuffer[tid + 1];
+            barrier();
+        }
+    }
+
+    if (tid == 0)
+    {
+        g_v[gid] = localBuffer[tid];
+    }
+}